Method and means for strand dispersal



Nov. 26, 1968 s. A. CANFIELD 3,412,914

METHOD AND MEANS FOR STRAND DISPERSAL Filed March 18, 1966 4 Sheets-Sheet 1 i INVENTOR SHEL DON ,4. CAMP/5L0 1968 s. A. CANFIELD 3,

METHOD AND MEANS FOR STRAND DISPERSAL Filed March 18, 1966 4 Sheets-Sheet 2 INVENTOR 5HL 00v 4. C/WF/ELD Nov. 26, 1968 s. A. CANFIELD METHOD AND MEANS FOR STRAND DISPERSAL 4 Sheets-Sheet 3 Filed March 18, 1966 Nov. 26, 1968 s. A. CANFIELD 3,412,914

METHOD AND MEANS FOR STRAND DISPERSAL Filed March 18, 1966 4 Sheets-Sheet 4.

I NVENTOR O in/H540 United States Patent C) 3,412,914 METHOD AND MEANS FOR STRAND DISPERSAL Sheldon A. Canfield, Newark, Ohio, assignor to Owens- Corning Fibcrglas Corporation, a corporation of Delaware Filed Mar. 18, 1966, Ser. No. 535,608 27 Claims. (Ci. 2267) ABSTRACT OF THE DISCLOSURE Method and apparatus for controlling the distance of separation of strands from each other in a group of strands in an ambient fluid stream surrounding and traveling with the group through contiguous fluid by varying the pressure of one fluid with respect to the pressure of the other fluid. This may be accomplished by restriction, venturi, or spaced nozzle means disposed in the path of said group to receive the passage of the group therethrough.

This invention relates to method and means for strand dispersal in general; and, more specifically, to a method and means for dispersing or separating strands from each other when the strands are traveling in a substantially parallel arrangement so that the strands may be more widely distributed and a controlled distribution may be obtained of the strands upon a receiving surface, as in when forming continuous strand mat.

Mats of fibrous glass, because of their inherent properties, especially those of strength and inertness, have many uses. They have been employed as filtering, acoustical and thermal insulating media. They also serve effectively for roofing sheets, non-woven fabrics, and for reinforcing plastic products.

In some instances the mats are composed of short fibers held together by a binder. In others the mats are bonded webs of chopped fibrous glass strands. Bundles or strandsof continuous glass filaments have also been disposed in mat form. Strands of filaments have superior strength because of the continuous nature of the filaments and their concentrated linear association in strand form. Accordingly, fibrous glass strands are a most desirable mat constituent where strength is a prime consideration.

However, there have been difliculties involved in the fabrication of strand mats as well as deficiencies in such mat products. Because of the comparatively greater bulk of the strands of standard fibrous glass, they are not inclined to become easily entangled to form an integrated mass. They also are not disposed to lie in a flat formation. A further objection has been that the production of such mats has been costly due to requirements of special equipment and slow and involved processing.

Also, in mats of conventional strands there is a lack of integrity, insutficient porosity, and a coarse appearance.

Some of these deficiencies have been overcome by partial filamentizing of the strands by impingement against a deflecting surface before the strands are massed in mat form. The resulting fuzziness promotes interengagement of the strands or semi-felting action which tends to integrate the mat product. However, there is an attendant bulkiness and loss of strength which are undesirable for many end uses of the mat. In addition, areas where there is a concentration of dispersed or fuzzed strands resist desired penetration by a resin to be reinforced.

This has been overcome to some extent by the provision in the prior art of method and apparatus for drawing continuous filaments from a single forming station, gathering the filaments into a plurality of strands rather 3,412,914 Patented Nov. 26, 1968 than int-o a sin le strand, and projecting the plurality of strands in parallel and substantially planar formation back and forth across a conveyor to form a mat of strands thereon. However, in the projection of the plurality of strands in substantially parallel formation the problem has arisen that the pattern area covered by the strands on the collecting surface is relatively small. As an example, in one continuous strand mat forming process the strand is ejected from a wheel puller about five feet above the collection conveyor. However, in spite of this large distance, the pattern is relatively small and appears to be largely due to a necking-in of the fibrous strands in the zone immediately below the wheel puller ejecting them. This necking-in is due to a zone of reduced pressure interior of the strand bundles caused by the high velocity of induced or ambient air carried by or pumped" by the high velocity of the moving strands. The pressure at the contiguous or surrounding exterior of the group of strands is greater than the ambient pressure interior of the group preventing wide dispersion of the strands on their path to the collection conveyor or accumulating surface.

In view of the above, it is an object of this invention to provide a method and means for dispersing strands from each other.

It is a further object of this invention to provide method and means for more expeditously and economically producing superior mats of strand material.

A further object of this invention is to provide a novel method and means for manufacture of strand mats having high integrity and strength.

In attaining the foregoing objects, this invention features apparatus for controlling the distance of separation of strand from each other in a group of strands traveling in substantially parallel relationship which comprises means for varying the pressure of fluid contiguous to the group of strands with respect to the pressure of the ambient fluid surrounding and traveling with the group of strands.

In a preferred embodiment of this invention the pressure varying means comprises a venturi means having convergent-divergent side walls forming a restriction. The venturi means is positioned to accept passage of the group of strands between the side walls. The amount of dispersal or the distance of separation of strands may be further controlled by including means for controlling the amount of variance of pressure contiguous to the group of strands. In a preferred embodiment this is attained by applying the pressure variance at or after the restriction formed by the side walls of the venturi means. To attain a certain effect, the control means may include means for lowering the contiguous pressure, or raising the contiguous pressure depending upon the separation desired between the strands. Again in the preferred embodiment this control means includes means for projecting a fluid stream with a relatively higher velocity than the strands at the restriction traveling in substantially the same direction as the group of strands.

Advantageously, the convergent portions of the side walls of the venturi means include lip means extending through the restriction. Plenum means may be utilized communicating with the strand adjacent urfaces of the side walls and may communicate with said surfaces via apertures formed through the side walls behind the lip means. A variable pressure means may be connected to the plenum means.

The apparatus of this invention may further include a pull wheel means to eject the group of strands into the substantially parallel travel and the venturi means may include a mounting means or a back plate for the side Walls wherein the back wall means is disposed adjacent to the periphery of the pull wheel to aid in channeling the ambient air surrounding the group of strands through the restriction. The pull Wheel means may further include an oscillatable means operative to vary the point of ejection of the group of strands from the periphery of the pull wheel means. Means responsive to the movement of the oscillatable means may be utilized for maintaining the venturia means disposed to receive the passage of a group of strands through the restriction.

The preferred embodiments shown herein illustrate the novel method for controlling the distance of separation of the strands from each other, which comprises the step of varying the pressure of fiuid contiguous to the group with respect to the pressure of ambient fluid surrounding and traveling with the group of strands. The varying step may include the step of passing the ambient fluid surrounding and traveling with the group of strands through a restriction means. As noted in the description with respect to apparatus, the step of controlling the pressure of the contiguous and ambient fluids at a restriction may be utilized to control the amount of separation, as desired.

Although the principles of the present invention are described as applied in the use of glass strands, the invention is not limited thereto in view of the fact that it has aspects readily applicable to use with strands, yarns and other forms of different materials. For example, the described method of effecting strand dispersal can be used for the dispersal of yarns or slivers as well, or may be used for dispersal of strands, yarns or slivers of materials such as cellulose acetate, artificial silk, cotton, wool, or nylon.

Other objects, advantages and features of the invention will become readily apparent when the following description is taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a front elevation of apparatus to which the invention may be applied;

FIGURE 2 is an enlarged plan view of the apparatus in FIGURE 1, with an additional pair of pull wheels and the equipment associated therewith;

FIGURE 3 is a side elevation with portions in section of one of the pull wheels and the motor drive therefor incorporated in the apparatus of FIGURES l and 2;

FIGURE 4 is a fragmentary front view with parts broken away of the pull wheel and motor drive of FIG- URE 3 with the assembly turned 90 counterclockwise from the position of FIGURE 3;

FIGURE 5 is a side elevation of the pull wheel illustrated in FIGURE 3 showing the association therewith of a first embodiment of a strand means according to this invention;

FIGURE 6 is a partial view of the apparatus of FIG- URE 5 taken from the left and showing a side view of the dispersal means;

FIGURE 7 is a partial side view of the apparatus of FIGURE 5 taken from the right side showing the remaining side view of the strand dispersal means plus the means for effecting adjustable attachment of the strand dispersal means to the pull wheel means;

FIGURE 8 is a front elevational view of a second embodiment of the teachings of this invention;

FIGURE 9 is a front elevational view of a third embodiment of the teachings of this invention; and

FIGURE 10 is a front elevational view of a fourth embodiment of the teachings of this invention.

Referring to the drawings in more detail, the apparatus of FIGURES l and 2 includes molten glass feeding bushings 21 and 22 depending from conventional glass melting tanks which are not illustrated. A second paired set of bushings 21a and 22a is depicted in FIGURE 2. The additional equipment of FIGURE 2 duplicates that of FIGURE 1 and will not be described separately. The main components carry the same identifying numbers as the like parts of the apparatus of FIGURE 1 but with the letter a following each number.

Continuous filaments 23 are drawn from the minute streams of molten glass issuing from orifices of the bushings. It will be considered that a bushing with three hundred and fifty to four hundred orifices is here utilized and the filaments are drawn to an average diameter of fifty 0ne-hundred thousandths of an inch.

Size is applied to the filaments as the latter pass over the traveling belt or aprons of the conventional size applicators 25. The size may merely be water to reduce friction between filaments as they are subsequently joined together in strand form. A more complex size or binder is, however, desired to promote coherence of the filaments when combined as strands, and adherence of the strands of filaments to the surfaces of the pulling wheels. Where the mat produced is to be ultimately combined with a plastic resin, it is also desirable to include a coupling agent in the size which facilitates wetting of the mat by the resin.

A preferred form of binder is one retaining sufficient cohesive properties when cured to contribute to the bonding of the strands in the mat or other form in which they are collected on the conveyor or receiving surface. Such a. binder has the dual purpose of holding the filaments together as strands, and bonding the strands into an integrated body.

If the mats are produced immediately below the glass filament forming stations, a commonly used lubricant component of the size may be omitted. The inclusion of such a lubricating material has been found necessary for improving the handleability of the strands where the strands go through subsequent operations such as plying and twisting, but it is not otherwise necessary and in fact interferes with effective wetting of the strands by a plastic resin.

The filaments from each bushing, after sizing, are in this instance grouped together to form sets of from Six to fourteen strands individually segregated as they travel within six to fourteen grooves over the respective gathering shoe 27. Each strand will then contain from about sixty filaments to about twenty-five filaments, depending upon the number of strands into which the filaments are individually segregated. The diversion of filaments into strands is here accomplished manually at the start of operations.

The sets of strands 29 and 30 pass under the aligning shoes 31 which are grooved in the same manner as the gathering shoes 27.

To help keep the pull wheels clean of size and to distribute the wearing action of the strands on the pull wheel, the aligning shoes may be given a slight traversing action. This slowly shifts the strand position on the pulling wheel, moving back and forth about once in three minutes.

From shoes 31 the two sets of spaced strands 29 and 30 are led around the two idler wheels 33 and respectively travel around the pull wheels 35 and 36. These wheels are similarly constructed but are relatively reversed in position and are on opposite sides of the center line of the receiving conveyor 61.

Motors 37 and 38, respectively, drive pull wheels 35 and 36. The strands carried by pull wheel 35 are released therefrom by the successive projection of fingers of oscillating spoke wheel 39 through slots in the peripheral surface of the pull wheel 35, while the fingers of spoke wheel 40 serve this purpose in connection with pull wheel 36. The strands are kinetically projected in tangential paths from the pull Wheels.

The rear side of each pull wheel is covered by an independently mounted, oscillatable back plate on which the associated spoke wheel is carried. Back plate 42 of the assembly including pull wheel 36 is arcuately oscillated through arm 43. The latter is driven by functioning of the fluid cylinder 52 which acts through the triangular link 45, which pivots upon bar 47 on the base 49. The piston rod 53 extending from the cylinder is joined to the triangular link by a linking rod 54. The base 49 is positioned on the platform 50 which also supports the pull wheels 35 and 36 and the equipment associated therewith. Platform 50 is suspended by angle iron handers 51.

Through the connecting assembly 55, including the turn buckle 56, the transverse movement of the triangular link 45 is transmitted to arm 57 to arcuately oscillate back plate 41 and thus the spoke wheel 39 within the pull wheel 35. This oscillation is preferably in an arc of approximately 57. With the single means effecting the oscillation of both spoked wheels, their action may be closely synchronized.

The group of strands 58 thrown down by the pull wheel 35 and the group of strands 59 thrown down by the pull wheel 36, and the strands from any other pull wheels preceding this pair are accumulated in mat form 60 upon traveling conveyor 61, which is preferably of carbon steel chain construction.

The width of the conveyor covered by the mat in this case is four and one-half feet, but this may be varied through a wide range by changing the oscillating arc length of the spoked wheels and the distance of the pull wheels above the conveyor. The side shields 62 and 63 are mounted to adjust their spacing to match the width of the deposited material. Ordinarily, the width utilized would be between extreme limits of two and nine feet.

The pull wheel 35 and the drive there-for are shown in more detail in FIGURES 3 and 4. On the shaft of motor 37 is a toothed pulley '64 which has driving connection through the segmented timing belt 65 with toothed pulley 66. The latter is mounted on the outer end of shaft 67, on the other end of which is carried the pull wheel 35.

The shaft 67 is journaled in the stationary casing 69 upon which the motor 37 is supported. The pull wheel is held upon the threaded stud 71 of the shaft 67 by the barrel nuts 72. The hub 73 of the pull Wheel has a bored section fitting over the smooth portion of the stud 71 and held against a shoulder terminating the smooth portion by the barrel nut 72. The main body of the pull wheel is fastened to the hub 73 by machine screws 75 and 76. A cap 78 covers the outer end of the bore through the hub.

In a preferred embodiment, the pull wheel 35 is twelve inches in diameter and has a series of peripheral cross slots 81, approximately one and one-eighth inches long, three-sixteenths of an inch wide and spaced five-sixteenths of an inch apart. To reduce the wear, the strand receiving surface of the pull wheel is given a hard surface such as an electrolytic deposit.

The fingers 83 of the spoke wheel 39 within the pull wheel 35 are dimensioned and motivated to successively project through the slots 81. The spoke wheel is mounted on shaft 87 projecting from the back plate 41 and carries the toothed pulley 89 on a rearward extension of the wheel hub 73.

The main body of the spoked wheel 39 is in this instance about three and three-quarter inches in diameter with the fingers 83, twenty-seven in number, radially extending slightly more than thirteen-sixteenths of an inch from the periphery of the main body. The exterior portions of the fingers are generally of rectangular blade from one inch wide with a thickness of .024 of an inch. About oneeighth of an inch of the outer end of the fingers extend out of the pull wheel slots at the point of their greatest projection.

The movement of the fingers 83 into the slots 81 and their momentary projection through the slots to release the strands is synchronized through the timing drive between the pull wheel and the spoked wheel. This includes the toothed pulley 91 fixed upon hub 73 of the pull wheel, the cog timing belt 93 running over the pulley 91, and the pulley 89 on the shaft 87 upon which the spoked wheel is journaled.

The back plate 41 oscillatable through yoke 57 to which it is attached, is mounted through hearings on the stationary casing 69. Yoke 57 and therethrough back plate 41 and the spoke wheel 39 are oscillated in an are of approximately 57 in this instance by the functioning of the fluid cylinder 51.

Air movement into the interior of the pull wheel. 35 is curtailed by the shroud ring held to the inner edge of the wheel periphery by a series of machine screws. A baflle 95 interruptedly cylindrical in form is carried by the oscillating back plate 41 and lies under the slots 81 except for an open section of the baflle in the region of the spoke wheel. This prevents air movement outwardly through the slots which is apt to irregularly release strands from the pull wheel. As the baffle oscillates with the spoked wheel, the opened portion of the bafile is always in the area where the fingers '83 enter the slots 81 of the pull wheel.

With the high peripheral speed of the pull wheels, the strands are forcefully projected into straight tangential lines from the oscillating point of disengagement effected by the fingers of the spoked wheel. The kinetic energy the strands thus acquire carries them to the region of the conveyor surface. Here they are self-positioning in lazy whirl formation with each strand assuming an individualistic pattern but disposed in inter-engaging and interleafing relation with the other strands of the set.

The distance of the pull wheels above the conveyor, and the rotational speed of the wheels are so selected, in relation to the specifications of the plurality of strands being deposited, that the strands are projected with sufficient kinetic energy to carry them as a band to the surface of the conveyor or other collection surface. The group of strands is thus deposited in a reciprocating strip disposed in a constant repeating pattern.

However, in spite of the comparatively large distance of the wheel puller above the collection conveyor the pattern area covered by a set or group of strands on the collection chain is relatively small. This is largely due to a necking-in of the fibrous glass strands in the zone immediately below the wheel puller ejecting them. This necking-in as noted by the dotted line configuration in FIGURE 5 and indicated by the reference character 58a is due to a zone of reduced ambient pressure interior of the strand bundles caused by the high velocity of induced ambient air carried by or pumped by the high velocity of the moving strands. The contiguous pressure at the surrounding exterior of the strand bundles after they leave the pull wheel 35 in FIGURE 5 is greater than the pressure interior thereof preventing wide dispersal of the strands upon their path to the collection conveyor.

In a preferred embodiment of this invention, this condition has been alleviated by directing a wheel pulled group of stands through a venturi structure to create an equalization of pressure throughout the strand bundles, eliminating the pressure gradient across the strand bundler and therefore providing 'for a Wide dispersion or throw of the fibrous strand bundles as indicated in FIGURE 5 by reference characters 58b denoting the position of the outermost pair of stands of the dispersed group. This apparatus, coupled with the oscillation devices, will provide a wide, uniform, full conveyor coverage layer of fibrous strands in the mat being formed.

Referring to FIGURES 5, 6 and 7 the details in positioning of the strand dispersal means of this invention is illustrated. Strand dispersal as effected by the preferred embodiment of this invention is provided by the use of a venturi means generally indicated at 100. The venturi means comprises side wall means 101, 102 mounted upon a back plate means 110. Side wall 101 has a convergent portion 103 and a divergent portion 14. Similarly, side wall 102 has a convergent portion 105 and a divergent portion 106. These convergent-divergent side walls are positioned, normal to or perpendicular to the plane defined by the parallel strands, in opposition on back plate to provide a venturi-type restriction. Back plate 110 has an upper lip 111 that is flared toward the periphery of the pull wheel to aid in channeling the ambient air surrounding and traveling with the group of strands 58 through the restriction formed by the side Walls 101, 102.

The venturi means is supported upon bearing blocks 112 and 113 which are secured to the back plate 110. The bearing blocks 112 and 113 journally receive a shaft 121 which is secured to bracket Bracket 120 is fastened to back plate 41 of the pull wheel 35 by bolts 122, 123 secured through a slot 124 formed in bracket 120, the slot affording an adjustment for the positioning of the venturi means. After the bearing blocks 113 are journally mounted upon the shaft 121, the securement of the venturi means may be effected by the tightening of the bearing slots formed in the bearing blocks 112, 113 by squeeze bolts 112a, 113a. Additional support and adjustment for positioning of the venturi means is provided by the support block (best seen in FIGURE 6) also journally mounted on shaft 121 and having a pin 131 extending through block 130 and behind and in contact with back plate 110. After block 130 has been rotated into the desired position, its position may be sesured by the tightening of bolt 132 which closes the hearing slot leading to the bearing surface for the shaft 121 and secures the block to the shaft 121.

The side walls 101, 102 have plenums 140, 141 formed therein. These plenums are connected to a variable pressure source 250, which includes valve means 251 for varying air flow from a pressure source 252 and valve means 253 for varying air flow to a suction system 254,

via conduit 142. The converging portions 103, 105 of the side walls have lip means 103a, 105a extending through the restriction formed by the convergent-divergent side walls. The plenums 140, 141 communicate with the strand adjacent surfaces of the side walls 191,. 102 via apertures, slots, etc., formed in the strand adjacent surfaces behind the lip means 103a, 105a of the converging side walls 103, 105.

Thus, a high velocity fluid of air stream may be ejected, from the slots formed "beneath the extending lip means, to travel substantially in the same direction as the travel of the group of strands 58 coming from the pull wheel 35. These fluid streams may be utilized to affect the pressure of the contiguous air surrounding the group of strands 58. A high velocity stream along the boundary layer adjacent the diverging side walls will lower contiguous fluid pressure. Alternatively, air may be withdrawn via plenums 140, 141 to also effect the pressure of the air or fluid adjacent the restriction and adjacent the group of strands 58.

It is to be noted in this embodiment that the relative value of the contiguous air pressure with respect to the ambient air surrounding and traveling with the group of strands 58 has already been affected by the passage of the strands 58 and the ambient air through the restriction. Even without operation of the control plenums and pressures, the venturi will obtain a wider dispersal of the strand. However, plenums and 141 which communicate with the strand adjacent surfaces of the side walls .101, 102 may be utilized to control or to vary this relationship of internal and external pressures of the air within and without the group of strands.

The air pressure variance by plenum operation may also be controlled with respect to time on a periodic or cyclic order so that a dispersal of the strands is effected according to the pressure variance control. Periodic variance of the contiguous pressure may be synchronized with periodic Variance of contiguous pressure at other forming stations so that a desired pattern or overlay may be .developed. Further, it may be desirable to vary the contiguous pressure according to the oscillation of the wheel so that strand dispersal means herein shown may broaden the band for a throw near the center of the mat and narrow the band for a throw at the edges of the mat. By thus broadening and narrowing the band for a throw at the collecting surface, a more uniform deposition will result.

Referring to FIGURE 8, there is illustrated dispersal apparatus having converging side walls 161, 162 mounted on back plate 163. A substantially parallel group of strands is passed between a restriction formed by the side walls 161, 162. The expansion of the ambient air interior of the group, surrounding and traveling with the strands, after passage of the strands and the ambient air through the restriction will disperse the strands. To control the amount of dispersion control nozzles 165, 166 may be mounted to direct fluid streams 167, 168 to vary the pressure of the contiguous air with respect to the ambient air traveling with the strands, to obtain dispersal as discussed hereinbefore.

Referring to FIGURE 9, there is illustrated a pair of nozzle means 170, 171 which may be positioned adjacent a group of strands to direct fluid streams 172, 173 to change the pressure of the contiguous air with respect to the ambient air traveling with the group 180 and effect dispersal as desired.

It should be noted that variations of the method and apparatus taught in this invention may be made to attain the desired results. For example, venturi-type apparatus may be utilized having one straight wall and one converging side to effect dispersal. With this variation, the strands would be dispersed toward the restricting side.

it should be further noted that the invention described herein may be utilized to increase the distance of the throw of the strands over that normally obtained from a means for imparting kinetic energy to the group of strands. That is, by increasing the velocity of the fluid or air contiguous to the group of strands and thereby lowering the pressure of the contiguous fluid or air with respect to the pressure of the ambient fluid or air surrounding and traveling with the group of strands, the resistance to travel of the group of strands is lowered. This allows the group of strands to be thrown or to travel a greater distance.

The ability to throw the strands further increases the width of the mat or other product that may be formed, without losing the accuracy of deposition required for uniformity of the product.

When great widths are being deposited, it may be desirable to lower the speed of travel of a group of strands near the middle of the deposition area, to prevent a high impact speed and impingement or non-uniform deposition. The speed of travel may then be controlled with the present apparatus by reducing the velocity of the jets adjacent the group of strands and varying the contiguous air pressure upward during that part of a cycle in which the strands are being deposited in the middle of the sweep. This assumes, of course, that the kinetic energy imparting means is stationed in approximately the middle above the collecting surface. If the kinetic energy imparting means is stationed at some other point above the collecting surface, then the contiguous air pressure would be varied upwardly at that part of the cycle when the kinetic energy imparting means was directing the strands downwardly toward the closest area of the collecting surface. In short, during a projection into a cyclic path of travel the distance of travel of the group may be varied at selected points within the cycle by varying the contiguous pressure as noted.

Referring to FIGURE 10, there is illustrated a fourth embodiment of the strand dispersal means of the invention. Strand dispersal is again effected by the use of a venturi means indicated generally at 200. The venturi means comprises side wall means 201, 202 mounted upon a back plate means 210. Side wall 201 has a convergent portion 203 and a divergent portion 204. Similarly, side wall 202 has a convergent portion 205 and a divergent portion 206. These convergent-divergent side walls are positioned in opposition on back plate 210 to provide a venturi-type restriction. The venturi means 200 may be supported adjacent a kinetic energy imparting means in any suitable manner, e.g., in the manner shown in FIG- URES 5, 6 and 7.

The side walls 201, 202 may have plenums 240, 241 formed therein. Plenums 240, 241 may be connected to a variable pressure source in any suitable manner, e.'g., as shown in FIGURE 6. The converging portions 203, 205 of the side walls have lip means 203a, 205a extending through the restriction formed by the convergent-divergent side walls. The plenums 240, 241 communicate with the strand adjacent surfaces of the side walls 201, 202 via apertures, slots, etc., formed in the strand adjacent surfaces behind the lip means 203a, 205a of the converging side walls 203, 205.

As in previous embodiments, a high velocity fluid of air stream may be ejected from the slots formed beneath the extending lip means to travel substantially in the same direction as the travel of a group of strands through the restriction. These fluid streams may be utilized to affeet, the pressure of the contiguous air surrounding a group of strands. A high velocity stream adjacent the side wall is a boundary layer that tends to adhere to the side wall in a Coanda effect. Such high velocity streams lower contiguous fluid pressure with respect to the ambient fluid pressure surrounding and traveling with the strands, thereby causing the strands to disperse with respect to each other.

In order to regulate the dispersal of the strands, small jets or fluid from nozzles or apertures 220, 221 formed in the strand adjacent surfaces or divergent side walls 204, 206 may be used to impinge the boundary layers or streams from plenums 240, 241. Depending upon the magnitude of the control jets or streams from nozzles 220, 221, the boundary layer attachments to the side walls may be destroyed or affected in such a fashion as to move the boundary layers or streams away from the side walls. A reduced dispersal of the strands results. The control jets or streams are very small in magnitude compared to the boundary layer streams. Obviously, the control jets may be used simultaneously, alternately, selectively, etc., as a desired grouping of the strands is required.

It should be noted that the control jets may be used with a restriction or venturi means, even though boosts to the boundary layer streams are not provided by streams from plenums 240, 241, since the restriction and expansion of air traveling through the venturi means creates a natural boundary layer effect.

In conclusion, it is to be noted that the embodiments disclosed and described herein are meant to be illustrative only and not limiting in any sense. The embodiments described serves merely to illustrate the spirit and scope of the invention.

1 claim:

1. Apparatus for controlling the distance of separation of strands from each other in a group of strands traveling in substantially parallel relationship in an ambient fluid stream having an internal pressure surrounding and traveling with said group through continuous fluid having an external pressure comprising means for varying one of said pressures with respect to the other of said pressures, and means for directing said group of strands through said pressure varying means.

2. Apparatus as defined in claim 1 in which said pressure varying means comprises a venturi means having convergent-divergent side walls forming a restriction, said venturi means being positioned to accept passage of said group of strands between said side walls.

3. Apparatus as defined in claim 1 which further includes means for controlling the amount of variance of one of said pressures with respect to the other of said pressures.

4. Apparatus as defined in claim 2 which further includes means for controlling the amount of variance of pressure contiguous to said group effected by said restriction of said venturi means.

5. Apparatus as defined in claim 4 in which said control means includes means for changing the pressure adjacent said restriction of said control means.

6. Apparatus as defined in claim 4 in which said control means includes means for lowering the pressure adjacent said restriction.

7. Apparatus as defined in claim 4 in which said control means includes means for raising the pressure adjacent said restriction.

8. Apparatus as defined in claim 4 in which said control means includes means for projecting a fluid stream at said restriction traveling in substantially the same direction as said group of strands.

9. Apparatus as defined in claim 2 in which said venturi means comprises means for mounting said convergentdivergent side walls in opposition to form said restriction and plenum means communicating with the strand-adjacent surfaces of said side walls.

10. Apparatus as defined in claim '9 which further includes means connecting a variable pressure means to said plenum means.

11. Apparatus as defined in claim 9 in which said convergent portions of said side walls include lip means extending through said restriction, and in which apertures are formed through said side walls behind said lip means to provide communication between said plenum means and said strand-adjacent surfaces of said side walls.

12. Apparatus as defined in claim 9 which further includes a pull wheel means to eject said group of strands into said substantially parallel travel, and in which said mounting means for said side walls comprises a back wall means disposed adjacent to the periphery of said pull wheel means to aid in channeling said ambient air surrounding said group of strands through said restriction.

13. Apparatus as defined in claim 12 in which said pull.

wheel means includes an oscillatable means operative to vary the point of ejection of said group of strands from the periphery of said pull wheel means, and means responsive to the movement of said oscillatable means for maintaining said venturi means disposed to receive said passage of said group of strands through said restriction.

14. Apparatus as defined in claim 1 in which said pressure varying means comprises opposed side walls converging toward each other to form a restriction through which said group of strands is passed.

15. Apparatus as defined in claim 14 which further includes nozzle means adjacent said restriction adapted to project fluid to vary the pressure of the contiguous fluid with respect to the pressure of the ambient fluid.

16. Apparatus as defined in claim 15 which further includes means for impinging said fluid streams from said nozzles with control streams.

17. Apparatus as defined in claim 1 in which said pressure varying means comprises nozzzle means positioned adjacent a group of strands and adapted to project fluid to vary the pressure of the contiguous fluid with respect to the pressure of the ambient fluid.

18. Apparatus as defined in claim 17 which further includes means for impinging said fluid streams from said nozzles with control streams.

19. Apparatus as defined in claim 8 which further includes means for delivering a control jet to impinge said fluid stream to vary the eflect of said fluid stream.

20. A method for controlling the distance of separation of strands from each other in a group of strands traveling in substantially parallel relationship in an ambient fluid stream having an internal pressure surrounding and traveling with said group through contiguous fluid having an external pressure comprising the step of varying on of said pressures with respect to the other of said pressures.

21. A method as defined in claim 20 in which said varying step includes the step of passing said ambient fluid surrounding and traveling with said group through a restriction.

22. A method as defined in claim 21 which further includes the step of controlling the relative pressures of said contiguous and ambient fluids at said restriction.

23. A method for controlling the distance of separation of strands from each other in a group of strands traveling in substantially parallel relationship and for increasing the distance of travel of said group of strands comprising the step of lowering the pressure of fluid contiguous to said group with respect to the pressure of ambient fluid surrounding and traveling with said group.

24. A method as defined in claim 20 which further includes the step of projecting said group of strands into a substantially parallel relationship along a cyclic path of travel, and astep of varying the distance of travel of said group of strands at selected points within a cycle by varying the pressure of the contiguous fluid with respect to the pressure of the ambient fluid.

25. Apparatus for controlling the distance of separation of strands from each other in a group of strands comprising means for imparting kinetic energy to said strands to produce travel of said strands in substantially parallel relationship, the velocity of said strands inducing ambient air to flow with said group of strands, and restriction means in the path of said strands for receiving said group of strands and said ambient air flow to increase the velocity of said ambient air, the pressure of said ambient air increasing as the velocity of said ambient air decreases after passage through said restriction thus separating said strands from each other.

26. Apparatus as defined in claim 25 which further includes means for varying the pressure of air contiguous to said ambient air after passage of said strands through said restriction to control the distance of separation of said strands from each other.

27. Apparatus as defined in claim 26 which further includes means for controlling the amount of variance of pressure of said contiguous air.

References Cited UNITED STATES PATENTS 2,657,433 11/1953 Merriman l966 2,919,970 1/1960 Russell 226--97 X 2,961,698 11/1960 Rea 226-97 X 3,212,691 10/1965 Lockshaw 22697 X 3,262,181 7/1966 Hawkins et al. l966 3,286,896 11/1966 Kinney 22697 3,325,906 6/1967 Franke 226--97 X ALLEN N. KNOWLES, Primary Examiner. 

